*From farmers to MPs, debate over seed ownership and the role of foreign influences on agriculture is causing divisions in Ghana

The US embassy in Accra held a roundtable on biotechnology this month. The discussion, designed to promote candid dialogue between biotechnology supporters and sceptics, was attended by experts and campaign groups on both sides of the GM foods debate.

But one Ghanaian campaign group refused the invitation. "Our call for a moratorium on GM foods was met with an invitation to a closed-door discussion," said Duke Tagoe, of Food Sovereignty Ghana, which campaigns for greater transparency about GM foods. "We are deeply worried about what seems like an imposition of genetically modified foods on the good people of Ghana without any meaningful public discourse, compounded by attempts to stifle any opposition."

Food Sovereignty Ghana and other domestic organisations accuse the US and other foreign donors of promoting GM foods to west African countries, and tying aid to implementation.

According to a leaked cable, the US government was heavily involved in drafting Ghana's 2011 Biosafety Act, which provided a framework for the introduction of GM foods. The US aid department provided technical assistance and some funding.

The cable said biotech products were being sold in Ghana and GM seeds from neighbouring countries were likely to have migrated over its borders. US companies have begun requesting permission to conduct trials.

The US embassy in Accra declined to respond to a request by the Guardian to comment on its stance on GM food in Ghana, but claims about the arrival of GM are supported by public officials.

"GM foods are used in agriculture. This is something you cannot wish away because it has come and it is in practice," said John Odame Darkwa, acting chief executive officer of Ghana's Food and Drugs Authority (FDA). "We ensure that any food imported into the country is safe."

But campaigners say trials of GM foods, which the FDA admits have been carried out in Ghana, are a violation of the law, which states trials require the written approval of a new body, the National Biosafety Authority. The problem, they say, is that this authority does not exist yet.

"Trials are being conducted, but there isn't any framework in place," said Kweku Dadzie, from Food Sovereignty Ghana. "We are calling for a ban on the importation, cultivation, consumption, and sale of genetically modified foods and crops, until the people of Ghana are satisfied that such an important and irrevocable decision is a sound and proper one to make."

Dadzie points to a lack of public debate surrounding the passing of the Biosafety Act. Maxwell Kofi Jumah, MP for Asokwa, recently admitted on local radio that ministers lacked understanding of the issues.

Many opponents of GM crops have pointed to the role of multinational companies that sell GM "hybrid" seeds that do not self-pollinate, compelling farmers to buy new seeds from the same companies each year, as well as their pesticides and herbicides.

Tagoe said: "Farmers in Ghana have had their own way of keeping seeds year after year. If these policies are allowed to manifest, Ghanaian farmers will have to change money into foreign [currency] in order to purchase seeds from overseas firms. The economic impact on the lives of the farmers will be disastrous. The origin of food is seed. Whoever controls the seed controls the entire food chain. These seeds are not owned by any African entity, they are owned by American companies."

However, experts say there are advantages to the technology. The chief executive of CGIAR Consortium on agricultural research, Dr Frank Rijsberman, said: "Private companies could develop self-pollinating seeds that also provide higher yields, but they don't because it's not profitable.

"But at the same time, the quality of seeds that pollinate themselves is often not that great. It can be difficult for farmers to select the best seeds. The job of seed companies is to select seeds that will have a bigger yields. The best hybrid rice, for example, produce about 20% better yields than the best self-pollinating seeds."

Some say that, instead of looking at yield increases through GM, the focus should be on improving access to markets for the crops that are already being grown by greater investment in extension services and low-technology improvements in farming.

"There is huge potential to increase yields using low-cost and existing technologies," said Kanayo Nwanze, president of the International Fund for Agricultural Development, speaking at the Africa Agricultural Science Week in Accra last week. "In Africa, only about 6% of the total cultivated land is irrigated … It is estimated that irrigation alone could increase output by up to 50% in Africa.

"Small increases in fertiliser use in sub-Saharan Africa can produce dramatic improvements in yields. Post-harvest grain losses in sub-Saharan Africa average $4bn every year. This is food that could meet the nutritional needs of around 48 million people."

Rijsberman said farmers needed better seeds, but also required better access to inputs, access to markets, farming systems, and livelihood strategies. "These things would go a long way to improving yields and incomes in a country like Ghana," he added.